Sulfoacetic acid anhydrides and methods for their preparation



Patented Sept. 4, 1 951 UNITEDSTATES PATENT OFFICE SULFOACETIC ACIDANHYDRIDES AND METHODS FOR THEIR PREPARATION Curtis W. Smith, Berkeley,Calif., assignor to Shell Development Company, San Francisco, Oalifl, acorporation of Delaware N Drawing. Application April 26, 1950, SerialNo. 158,340

where R1 and R2 are hydrogen atoms or various substituent radicals.

It is my discovery that acid anhydrides of the foregoing variety can beprepared by reacting sulfur trioxide with a ketene, the reaction goingforward in an eflicient manner whenever the reactants are broughttogether in an anhydrous solvent medium.

Ketenes are a special class of ketones which undergo many reactions thatare non-analogous to those of the general class of carbonyl com pounds,which reactions are due to the presence of the structural arrangementC=C=O in the ketene molecule. They may be represented by the generalformula wherein the expressions R1 and R2, which may be the same ordifferent, represent members selected from the group consisting of thehydrogen atom and the various alkyl, aryl, aralkyl, alkaryl andcycloparafiinic radicals. When both R1 and R2 are hydrogen the compoundis ketene itself (CH2=C=O). When only one of the Rs is hydrogen, thecompound is classified as an aldoketene, whereas if neither of the Rs ishydrogen the compound is a ketoketene. While the invention will begenerally described and illustrated hereinafter with particularreference to ketene itself (since it is the preferred reactant of thegeneral ketene class), nevertheless, other ke-.

tenes may be employed provided the structural arrangement C=C=O containsthe only aliphatic multiple linkage in the compounds. Illustrativeexamples of particular ketenes suitable for employment in the presentinvention include ketene, methylketene, ethylketene, methylbutylketene,ethylisopropylketene, amylketene, diheptylketene, ethylcyclohexylketoketene, bis(trimethylcyclohexyl) ketene, phenylcyclohexylketoketene, dimethylphenyl aldoketene, decylphenyl ketoketene,phenylketene, benzylketene, diphenylketene, methylphenyllretene, anddibenzylketene.

Claims. (Cl. 260-327) The reaction of the present invention may beillustrated by the following general equation:

As noted above, when R1 and R2 are hydrogen atoms, the one reactant isketene itself and the product is the (inner) anhydride of sulfoaceticacid. Other reactions which are illustrative of the invention arepresented in the following table wherein there is indicated theparticular anhydride derived by reacting sulfur trioxide with theindicated ketene derivative starting material:

Table Ketene Reactant Acid Anhydrlde Product 1 Methylketene Inneranhydride of alpha-sulfopropionic acid. 2 EthylkcteneInnerianhydrideofalpha-sullobutyric 8C1 3 Phenylketene lnnerianhydridcof phenylsulfoacetic aci 4 Benzylketene Inner anhydride ofalpha-sulio-betaphenyl-propionic acid. 5 Methylbutylketenc Inneranhydride of alpha-methylalpha-sulto-hexanoic acid. (5 Amylketene Inneranhydride ofalpha-sulfoheptanoicacid. 7 Ethylcyclohexyl keto- Inneranhydride of alpha-cyclohexyl ketene. alpha-sulfobutanoic acid. 8Diphenylketene Inner anhydride oi diphenylsulfoacetic acid. 9Methylphenylketene. Inner anhydride of alpha-phenylalpha-sulfopropionicacid. 10 Dibenzylketene Inner anhydride ofalpha-benzylalpdha-sulfo-beta-phenylpropionic aci ll Phenylcyclohexylketo- Inner anhydridc ofphenylcyclohexyl ketenc.. sulfoacetic acid. 12Dimethylphenyl aldo- Inner anhydride of (dimethyl) pheketene.nylsulioacetic acid. 13 Dicyclohexylketoketene. Inner anydride of dicyclohexyl sulloacetic acid.

The method of this invention is conducted by bringing the ketene intoreactive engagement with the sulfur trioxide in a liquid such asdioxane, pyridine, (liquid) sulfur dioxide, carbon tetrachloride,chloroform or the like, which is inert under the reaction conditionsemployed and has the ability to dissolve or otherwise retain the keteneand sulfur trioxide reactants. In some cases, as with dioxane, forexample, the solvent forms a loose molecular combination, or adduct withthe sulfur trioxide, though in such cases the sulfur trioxide is readilyreleased to the ketene reactant. The reaction proceeds in the absence ofa catalyst and at temperatures preferably below 50 C. Highertemperatures should be avoided whenever possible since considerablecharring of the product ensues as reaction tent pratures" Substantiallyin excess of 50 C. are employed. The reaction pressure is not criticaland good results are obtanied using subatmosflpheric, atmospheric orsuperatmospheric pressures.

The respective ketene and sulfur trioxide reactants combine in equimolarproportions, and it is therefore preferable to so proportion thereactants, though good results are also obtained when either reactant isused in excess.

are gases at room temperatures""andabove,"the normal practice is firstto form .arsolutionzof thesulfur trioxide in an appropriate solvent :and

then to bubble the ketene into this solution,:pre- 1:

ferably with cooling since the reaction is exothermic in character. Therate of ketene addition is, not critical, it being satisfactory in mostinstances to add the same at a rate of fromzabout 0.1 to 1 mole perhour, per mole of sulfur trioxide present.

Whatever the nature of-the-solvent, the reactants and the reactionconditions employed, care should be taken to insure that the reactionmixture is maintained in the anhydrous-condition, for to the extent thatwater is present there is formed the conventional .sulfo-carboxylic.acid, in tead of: the desireddnner. acid anhydride. ,Under anhydrousconditions the anhydride is formed ifngood yields-,theconversion theretogenerally being in excess .of 50%., based on the amount of sulfurtriox-ide employed.

. The acid anhydrides f the, present. invention are useful for a number.of; purposes, having valuable insecticidal and plant regulatoryproperties, among others, for example. However, they have particularutility as intermediates in the preparation of-0ther products. Thus,ithas been discovered that they readil 'combine with the various monoand polyamines- (as illustrated in Example I below) to form variousamino and amido products, many of which are polymeric in character,while others, on treatment with dilute caustic, provide usefuldetergents. "It has also been'found that the acid anhydrides- 0f.:.thepresent; invention have'the useful property of combining with olefins;or olefin derivatives, to formsix+membered ring. compounds. "The latterreactionisillustratedin the followingequation, wherein R isany alkyl orother substituent, group which is freeof aliphatic unsaturation:

The products of'=the foregoing :equation, .on treatmentwith dilutecaustic; imturn yield prod ucts'of the type of 7 R'GH-CHzo-Ic news canand The present. invention...isillustrated in various of. itsembodiments .bysthe iollowing examples 1 1A--solution of sulfur trioxide-was -prepared by thegdropewise additionrof ell-grams, (0 .5,mole of;-

since ke- 1 tene and various others of the-ketenemeactants sulfurtrioxide to a stirred solution of 44 grains (0.5 mole) of dioxane in 150ml. of ethylene chloride with cooling. Ketene (CH2=C=O) was then bubbledinto the solution until approxi- 5 mately 0.5 mole of ketene had beenadded, the reaction inixture being maintained at approximately 1310.byrcooling -,during the addition of the ketene. The reaction mixture wasthereafter allowed to stand for 30 minutes at 15 C. The ,presence of theinner anhydride of sulfoacetic racid avasrthenjestablished bypreparation of the known anilinium sulfoacetanilide compound the-reaction proceedii 1g;in.accordance with the equa- :tion:

ore-o i Qz s l "This anilinium derivative was prepared by pour- 7 .ingthe. reaction mixture into a solution of 200 g. of aniline in an equalvolume of benzene with coolmg, the. resulting mixture, then beingallowed to, stand in the, ice ,box overnight. The slimy pr e-. cipitatewhich separated asa result of this =c0O1 ing step wascollected onafilterand recrystallized'from about'two"liters of absolute ethanol. The nicelycrystalline derivative weighed 70 g. after it had been dried in air. Themelting point, 229-23l 0., was in exact agreement with that of aniliniumsulfoacetanil-ide prepared by Stillich [J prakt. Chem., '74, 53 (1906)]from aniline and sulfeacetic acid. 1

. Anilz'nium.suljoacetanilide V 7 Theory Found M mNz QQ ic ox.osrernightynn'aaddit onal 5 1e. ofhle pure, P- 22.4227-.Q., aniliniums111foacetani-" The. .meltinglpoint. .oithe product, ::18l.-182: 0.,was. lower tharrthat previously reported by Stil- 11ch-(see above) :forthGzIIIODOEIIlHI'li -Im salt of suli'oaceticacid .(M.;P. ,187.- 188 0.).However, heating :zthesproduct with. aniline at 180-195. C.

for forty-.five minutes gave a-product.whose.-melt.-- ingpoint,22992319: 0., -.and:.mixed. melting point Were. in agreement withanilinium sulfoacetanilide. ;F0rmation.of .the monoanilinium product is.1 doubtless.attributable .to. minor amounts. of

water- .that;..unavoidably. crept. into the. reaction mixture, thereby.converting: aaminor. percentage of theinner acidanhydride .to.sulioacetic acid.

' EXAMPLE II Following. thev procedure outlined, in: the, fore- 5goingexample; :but; with the; substitution for the" ketene ofapproximatelyy mole oimethylketene,

1 benzylketene,- phenylketeneand methylphenyle ketene, respectively, in.the sulfur trioxide-containing solution, there: are readily obtained.the;

corresponding acidvv anhy rides, .here 1 those; of

alpha-sulfopropionic acid, .phenyl sulfoacetic acidand alpha-'phlralpharsulfopropionic acid.

ThenItrate-ffmm. the above. recrystallization.was concentrated to about1 00:1111,,zandcooled,inthe than the zprecedings.derivative. J It. wasrecrystala lized .from..alcohol.- benzene,- .butanol and ethanol.

Still other reactions, all of which readily go forward to produce theindicated sulfo-carboxylic acid inner anhydride, are presented in thetable presented above.

The invention claimed is:

1. The process comprising bringing a ketene of the general formulao==c=o into contact with sulfur trioxide in an anhydrous, liquidreaction medium, the resulting reaction proceeding in accordance withthe equation,

o=o==o so. Bro-(i=0 R: O1S

wherein R1 and R: are selected from the group consisting of the hydrogenatom and the alkyl, aryl, alkaryl, aralkyl and cycloaliphatic radicals.

2. The process comprising bringing a ketene oi the general formula intocontact with suiiur trioxide in a. liquid, anhydrous reaction medium ata temperature below about 50 C., the resulting reaction proceeding inaccordance with the equation,

wherein R1 and R: are selected from the group wherein R1 and R2 areselected from the group consisting of the hydrogen atom and the alkyl,aryl, alkaryl, araikyl and cycloaliphatic hydrocarbon radicals.

5. The inner anhydride 0! sulfoacetic acid.

CURTIS W. SMITH.

REFERENCES CITED The following references-are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,178,353 Werntz Oct. 31, 19392,411,823 Doumani Nov. 26, 1946

4. A COMPOUND HAVING THE FORMULA